Pressure indicator



Oct. 26, 1948. w. v. ESLINGER ET AL PRESSURE INDICATOR Filed Aug. 22,1944 Patented Oct. 26, 1948 PRESSURE INDICATOR Wallace Vernard Eslingerand William Nathaniel Barton, Arlington, Va.; said Wallace VernardEslinger assignor to Genevieve B. Eslinger, Falls Church, Va.

Application August 22, 1944, Serial No. 550,658

3 Claims. 1

This invention relates to pressure indicators, and more particularly toan improved pressure response mechanism for automatically andselectively indicating decreased pressure in each of the pneumatic tiresin use on a vehicle.

An object of this invention is to provide a device that will instantlyindicate small decreases in tire pressure. Another object is to providean attachment for motor Vehicles that may be readily adjusted to operatewith vehicles already in use. A further object is to provide such adevice that is selectively responsive and automatically adaptable to anycondition of road surface. Other more specific objects will appear fromthe detailed description presented herein when contemplated inconjunction with the drawings, which represent diagrammaticall in:

Figure I: A vertical cross-section View of the pressure response unitill, in its normal neutral position.

Figure II: A rear elevation of the housing I i with the rear cover l 2removed.

In Figure I the response unit it! comprises a casing l I, a removablecover l 2, a ball joint husing i3, having a cap i l, a ball member [6,and its retaining spring I 5.

The ball member i6 is provided with a rearwardly extending shank l1,terminating in plate member 68. The ball it, the shank ll, the plate 18, elbow 25, are all resiliently mounted by means of the spring 15, as arigid unit for limited movement in horizontal and other planes, in thehousing 53, and all resiliently held in normal neutral position by thesprings 18 attached to plate 3 and the housing l I.

Conveniently attached inside the casing II is the switch 20, from whichlead the conduits 2i, clearly shown in Figure II. The switch 20comprises an operating arm 22, pivoted at 23 and resiliently suspendedin a neutral position by the springs 24, between the two contact pointsof the conduits 2|.

Fixed to a portion of the ball 16 opposite the shank ii is the elbow 25,to which is pivoted at 26 the arm 21. Adjusting means such as the setscrew 37 and slotted arc members 33 are provided so that the arm 21 maybe set at any operating angle required for the type of wheel, tire andvehicle in use.

Recessed in the lower portion of the arm 2'! is the shaft 28 resilientlymounted for limited movement in a vertical plane by means of the spring29 retained in the recess 313. On the lower end of the shaft 28 ismounted a freely rotating cylinder 3| which is preferably provided witha smooth. rounded knob-like portion 32.

The response unit it may be fixed to the vehicle by welding or anysuitable means, or may be incorporated in the axle assembly duringmanufacture. Duplicate units may likewise be attached adjacent the otherwheels of the vehicle. In each case the conduits such as shown in 21 oneach of the mechanisms may be led in a manner well-known in the art tothe dash board of the vehicle where they may be connected to individuallights or to other signalling means, audible or visible.

The response unit I0 is attached to the vehicle or to the axle 34 in aposition so that the cylinder 3| is adjacent to but not quite touchingthe inner sidewall of the tire 35 when properly inflated, at the lowerportion of the inner sidewall of the tire just above the point oftraction between the tire and the road. This position of the cylinder 3|may be fixed, by adjusting the angle of the arm 2'! on its pivot 26 bymeans of an adjusting mechanism, such as shown at 37, and 33.

When the vehicle is in operation and all tires properly inflated, thecylinder 32, the shaft 28, the arm 21, the elbow 25, the ball 55, theshank H, and the plate 28 are all resiliently held in their normalneutral position as shown in Figures I and II.

If highway obstacles are encountered such as ruts, mud, boulders, ice,slush, sand or other obstructions, the knob 32 will ride over theseobstructions by means of the vertical floating shaft 28 and thehorizontal floating joint 56. Also, if after standing there is anaccumulation of ice or mud on the inner wall of the tire, theresiliently mounted roller and arm 2?, by means of the ball joint at it,will likewise ride over such accumulations on the tire until they areremoved by the speed of the rotation of the tire.

While the knob 32 and the rotatable cylinder 3! are contacting theseobstructions or accumulations the responsive movement of the arm 21 willbe transmitted through the elbow 25, the ball IS, the shank IT, todisplace the plate 58, which in turn will displace the switch operatingarm 22 out of its neutral position thereby completing the circuit in theswitch 20 between the conduits 2i which will in turn transmit thecurrent to the light or signal on the dash board to which they areconnected, in a series of intermittent flashes or signals.

When the pressure in the tire 35 decreases the side Wall will bulge andcome into constant contact with the cylinder 3| which will continuallyhold the arm 21, the elbow 25, the shank l1, and the plate 18, out oftheir neutral position, thereby keeping the electric circuit constantlyclosed in the switch 20 and the conduits 2|, causing the correspondinglight on the dash board of the vehicle to remain steadily illuminatedwithout any intermittent flashing or if an audible signal is preferred,it will remain constant without interruption. In every case the springl5, I9, 24 and 29, will return the response unit to normal position whenthe conditions described are removed.

It is apparent that adjustable extension means may be incorporated inthe arm 21 or in the shaft 28, so that the roller 3i ma be fixed in itsproper position for any type of vehicle or wheel. This adjusting meansmay take the form of straight interengaging slotted members (not shown)similar to the arcuate members shown at 33, which may be fixed in theiradjusted position by a set screw similar to that shown at 31. It is alsoapparent that adjustable brackets may be used for attaching the unit tothe vehicle, so that the roller 3| may be properly positioned asdescribed herein.

The housing 13, and the recess 39 if desired may be sealed and filledwith oil or non-freezing brake fluid on larger size units. Thiseliminates trouble from rust or dust and insures longer life.

When the present device is used on double tires it is applied so as tocontact the innermost of the two or more tires. It has been found bytests that any decrease in pressure in the outside tires will instantlythrow enough load on the companion tires to cause enough bulge toactuate the herein described indicator. Tests on heavy duty truckingtires have shown that the present invention will indicate decreases ofless than five pounds in tire pressure.

While we have herein described our improved pressure indicator in detailwith respect only to one preferred embodiment thereof, we do notcontemplate limitation thereto, but intend to include all forms andmodifications thereof within the scope and spirit of the appendedclaims.

We claim:

1. In a wheeled vehicle having pneumatic tires, a tire deflationindicator comprising a deflation response unit adapted to be mounted onsaid vehicle adjacent one of its wheels. said unit comprising tirecontacting means normally positioned to be engaged by the inner sidewall of the tire on said wheel when under-inflated at an area adjacentthe point of traction between said tire and the ground, primarysupporting means holding said contacting means for resilient limitedaxial movement in one plane, secondary supporting means holding saidprimary supporting means for resilient limited movement in other planes,a switch arm arranged in operating engagement with said secondarysupporting means and normally held in neutral position, whereby anymovement of said secondary means out of its normal position caused bytire deflation will move said switch arm out of its neutral position andinto an indicating circuit closing position.

2. An attachment for a wheeled vehicle having pneumatic tires, a tiredeflation indicator comprising a deflation response unit adapted to bemounted on said vehicle adjacent one of its wheels, said unit comprisingtire contacting means normally positioned to be engaged by the innerside wall of the tire on said wheel at an area adjacent the point oftraction between said tire and the ground, when said tire isunder-inflated, primary supporting means holding said contacting meansfor resilient limited axial movement in one plane, secondary supportingmeans holding said primary supporting means for resilient limitedmovement in other planes, a switch arm mounted in operating engagementwith said secondary supporting means and normally resiliently heldneutral position, whereby any movement of said secondary means out ofits normal position caused by tire deflation will move said switch armout of its neutral position and into an indicating circuit closingposition.

3. The combination described in claim 2 that includes means foradjusting the operating angle of said primary supporting means.

WALLACE VERNARD ESLINGER. WILLIAM NATHANIEL BARTON.

REFERENCES CITED The following references are of record in the file ofthis patent:v

UNITED STATES PATENTS Number Name Date 1,198,688 Young Sept. 19, 19161,947,760 Denhart Feb. 20, 1934 2,057,445 Prospero Oct. 13, 19362,191,205 Rogers Feb. 20, 1940 2,258,334 Miller Oct. '7, 1941 2,324,618Dietrich July 20, 1943 FOREIGN PATENTS Number Country Date 280,483Germany Nov. 9, 1913

